It is known that a modem totem-pole power factor correction circuit is illustrated in FIG. 1. If sensing the current flowing through an input inductor 9 connected in series with the totem-pole power factor correction circuit 8 is desired, a current sensor 7 connected in series between the input inductor 9 and a first bridge arm 81 of the totem-pole power factor correction circuit 8 is required. This type of series connection is illustrated in FIG. 1.
In the implementation of the circuit, however, it is necessary to select a Hall device as the current sensor, due to the change of polarity of the input inductor 9 as well as both high- and low-frequency components being simultaneously contained therein because the alternating current power source is applied. Although the Hall device is capable of detecting the current flowing through the input inductor 9, the Hall device is bulky so as to occupy larger wiring space, being unfavorable to the implementation of miniaturization appealed by modern electronic equipments. Besides, the choice of Hall device may lead to the increase in cost of overall circuit.